“pavement audit” for greenville and pickens counties
DESCRIPTION
“Pavement Audit” for Greenville and Pickens Counties. Diagnosis Report to Focus Group January 25, 2006. Presentation Overview. Lawrence Group Scope of Audit Audit Methodology Recommendations/Findings Questions/Feedback/Next Steps. The Lawrence Group. Founded in St. Louis in 1983 - PowerPoint PPT PresentationTRANSCRIPT
“Pavement Audit” for Greenville and Pickens Counties
Diagnosis Report to Focus Group
January 25, 2006
Presentation Overview
• Lawrence Group • Scope of Audit• Audit Methodology• Recommendations/
Findings• Questions/Feedback/Next
Steps
The Lawrence Group
• Founded in St. Louis in 1983
• Carolinas office in Davidson, NC
• Town Planning & Architecture
• Municipal, non-profit, and developer clients
Lawrence Group Projects
Mooresville, NC Code
Haynie-Sirrine Master Plan – Greenville, SC
General Development Guidelines – Research Triangle,
NC
Active Living Assessment
Concord-Roberta Church Small Area Plan - Concord,
NC
Woodlands-Davidson, NC
Belmont Reserve-Belmont, NC
Project Scope
Saluda-Reedy Watershed
“. . .non-point source pollution – sediment, nutrients and waste carried by storm water – is now the chief threat to these rivers. . .
It will take a concerted effort by
community leaders across the Upstate to effectively address the threats of non-point source pollution fed by rapid development . . .”
-SRWC
Project Scope
•“. . . audit of paving requirements in the codes and ordinances of Greenville and Pickens Counties. . .”
•“Identify opportunities. . .to reduce the amount of impervious cover generated by new development.”
Project Scope
Ordinances Reviewed
Greenville County
– City of Greenville
– Greenville LUDO– Fountain Inn
– Greer – Mauldin
– Simpsonville– Travelers Rest
Pickens County– Central
– Clemson– Easley– Liberty
– (Pickens)
Methodology
• Zoning Ordinances and Land Development Regulations
• Based on “Builders for the Bay” process (www.cwp.org)
• 10 major categories; 36 factors
Methodology
• Major Categories– Street width– Right-of-way width– Cul-de-sac design– Street drainage (swales v. curb
& gutter)– Parking ratios– Shared parking– Parking lot design– Parking lot landscaping– Sidewalks and planting strips– Driveways
Imperviousness
Rooftops + Car space
Transport-related impervious cover: 60-
70%(streets + parking
areas)
Roof tops: 30-40%
Imperviousness
Street Design
• Local Streets: 20-24 feet• Could be as narrow as 16-
18 ft
Street Width
• Minimum street widths
Street Width
Street Width
• Local Streets: 20-24 feet• Cul-de-Sac streets: 22-28
ft– Could be as narrow as 18 ft
• Manufactured home park streets: 20-28 ft– Should be same as local streets
• Alleys: 12-30 feet (Greenville County standard is
good: 12-18 ft)
Street Width
• Local Streets: 20-24 ft• Cul-de-Sac streets: 22-28
ft• Manufactured home park
streets: 20-28 ft• Alleys: 12-30 ft
(Greenville County standard is perfect)
• Collector Streets: 24-40 ft– Could be as narrow as 20 ft– Consider parking, bike lanes,
turn lanes
Curb Radii
• 25-40 ft (Greenville County)
• Pickens Co: Not specified• AASHTO Guidelines:
– Local/local: 10-15 ft
– Local/collector: 15-20 ft
– Collector/collector: 15-25 ft
Right-of-Way Width
• 40-50 ft; typically 50 ft
• Could be as narrow as 34-38 ft.
• Allow utilities in the street
Cul-de-sac Design
• Typical: 40 ft(Greenville: 41 ft; Clemson: 35
ft)
• Landscaped Islands: 8 of 13 allow
• Alternate turn-arounds: – Greenville: yes– Pickens: no
Cul-de-sac Design
• Cul-de-sac islands: – Greenville Co.: typically yes– Pickens Co: typically no
Open Channels/Swales
• Only Clemson, Easely, Liberty require curb & gutter on all streets
• Pickens County swales: < 2 dua; slopes “not excessive”
• Tom Schueler:– No slopes > 5%– Runoff velocities > 4-5 ft/sec.– Soils/climate don’t allow dense
turf– Water table < 1 ft below channel– No densities > 3 dua
Sidewalks
• Context-sensitive requirements– Based on street-type (Clemson)– Development density (> 2 dua)– Proximity to schools (1-1.5 miles)
• One side only generally• Alternate networks: 4/13
codes
Sidewalks
Street-type based (Clemson):
Density-based (FHWA):
Street-type
# of units Sidewalk
Cul-de-sac 25 SF/43 MF One side
Access 25 SF/43 MF One side
Sub-collector
62 Both sides
Collector 125 + Both sides
Commercial areas: Both sides
> 4 dua: Both sides
1-4 dua: One side
< 1 dua: None
Sidewalks
• Sidewalk width: typically 4 ft min
• ITE & FHWA: 5 ft min.
Planting Strips & Trees
• 5/13 codes require planting strip
• 2-3 ft wide– 6-8 ft recommended for street trees
• No codes require street trees• Benefits of trees
– Reduce runoff volumes– Increase soil infiltration– Increase soil water storage– Reduce erosion– Shade prolongs life of asphalt; reduces
runoff temperatures– Shade: cars, pedestrians, homes– Improve air quality– Aesthetics (= increased property
values)
Planting Strips & Trees
Parking Areas
Parking Ratios
• Wide variation in requirements
• Not based on reliable research
• Shopping Centers– 2-6 spaces/1000 sf in Greenville Co.– 4-5 spaces/1000 sf in Pickens Co.– 10 spaces/1000 sf for food stores in
Central, Easley, Liberty – ICSC: 4/1000 yields surplus 99% of
time
• Parking requirements waived in most CBD’s
Parking Ratios
Recommendations to consider:• Use draft Greenville LUDO
model– Low minimums (2/1000 sf for
retail)– Maximums (use current minimums)
• Allow on-street parking to count
• Waive/reduce parking req’mts in all CBD’s and other mixed-use nodes
• Reduced minimums for transit service
Shared Parking
• All codes allow except Clemson
• No incentives for sharing• 50 or 100% of spaces may
be shared • “each parking space may
be counted for each activity” (Central, Easley, Liberty)
• Greenville LUDO offers more complex/accurate formula
Parking Lot Design
• Stall width: 8.5-9 ft• 2 rows & aisle: 60-64 ft
– 60 ft is adequate
• Compact spaces: 3/13 codes– Limited benefit
• Pervious Pavement (good!):– Wide variation: not allowed;
allowed; required– Pickens Co.: allowed but not
req’d– Greenville Co.: req’d for 100-
200% over minimum
Parking Lot Design
Parking Lot Landscaping
• Greenville Co.: All but Fountain Inn
• Pickens Co.: Clemson, Easley• Range of applicability:
– 1-60+ spaces; new and/or expanded
– Clemson, Greenville Co. extremes• Required planting:
– Greenville Co.: ~ 1 tree/10-20 spaces
– Pickens Co.: 5-10% of area• No required curbing: Good!• No biorention
encouraged/required
Parking Lot Landscaping
Bio-rentention
Parking Lot Landscaping
Bio-rentention: Wilmington, NC
Driveways
• Clemson & Mauldin allow permeable driveways(all other codes silent)
• Residential Setbacks: 15-40 ft; generally 20+– Reduce front setbacks to 20 ft
or less
Other Issues
• Minimum lot size– Consider minimum density
instead– Provide incentives for clustering
• Encourage Alleys in higher density SF (8+ dua)
• LEED-ND (Leadership in Energy and Environmental Design)
• Land use policies– Greater density = less impact
• Transportation Demand Management
Next Steps
Questions/Discussion